Issue jedbrown#36: Changed an 'echo' to 'printf' for portability and robustness.

Author: Nathan A. Wukie

FindPETSc.cmake

@@ -156,7 +156,7 @@ if (petsc_conf_rules AND petsc_conf_variables AND NOT petsc_config_current)
 include ${petsc_conf_rules}
 include ${petsc_conf_variables}
 show :
-\t-@echo -n \${\${VARIABLE}}
+\t-@printf '%s' \${\${VARIABLE}}
 ")
 
   macro (PETSC_GET_VARIABLE name var)